Real-time organic compounds monitoring in advanced oxidation process (AOP) of sewage digestion tank wastewater: introduction of UV-VIS spectrum representative index by discrete Fourier transform

Anaerobic digestion effluent from sewage treatment plants (STP) is challenging because of high organic matter and inorganic nitrogen concentrations, which require an effective process for biological treatment. The study aimed to introduce a UV-VIS spectrum representative index by discrete Fourier transform (DFT) and apply UV/Vis spectrophotometric techniques for the real-time organic compounds monitoring in the AOP process using anaerobic digestion tank effluent wastewater. However, the effect of advanced oxidation on the organic compounds of effluent using ozonation was examined. Therefore, in this research, after treating secondary treated water with the UV-AOP process and anaerobic digestion effluent with ozone microbubble systems, changes in organic substances were expressed by the UV-VIS spectrum and compared with conventional water quality parameters. The anaerobic digestion tank effluent was subjected to ozonation, had a high curve, and fell gently from 230 nm to 667 nm. Discrete Fourier Transform (DFT) was applied to obtain representative values from the obtained spectrum. Among the coefficients obtained by analyzing the UV-Vis spectrum by DFT, an expected value was selected, and the correlation between COD Mn and a3 was the highest (correlation function = 0.694, RSQ = 0.482). Therefore, a linear regression analysis was performed to determine which water quality factor it was related to.